Discrepant
Events
Ms. Youngjee Kim
Battery Park City School
1
Table of Contents
Discrepant Events:
Page
1. Baking Soda + Vinegar = What
Put Out the Fire?
3–5
2. Oobleck! Liquid or Solid?
6–7
3. The Candle, the Beaker and
the Water?
8–9
4. Diet Coke and Mentos®:
Coke Volcano?
10 - 12
2
Baking Soda + Vinegar =
What Put Out the Fire?
• Overview:
Placed a small candle inside a beaker
and added a small amount of baking
soda and water. Then lit the candle
and poured a small amount of vinegar
into beaker.
• Question:
Why did the flame go out when liquid
was poured into the beaker?
3
Baking Soda + Vinegar =
What Put Out the Fire?
• Explanation:
This is a multi-step reaction:
A) Acetic Acid (the vinegar) reacts with
sodium bicarbonate (baking soda)
to form carbonic acid.
B) Carbonic acid is unstable and
immediately separates into carbon
dioxide and water. The bubbles are
a result of the reaction that comes
from the carbon dioxide escaping
like that of a bottle of soda.
4
Baking Soda + Vinegar =
What Put Out the Fire?
This activity shows the existence of
an invisible substance that put
out the fire. When vinegar is
poured into the dissolved
baking soda, carbon dioxide is
released. The carbon dioxide
fills the beaker, pushing out the
oxygen and extinguishing the
flame.
What is left in the container is a
dilute solution of sodium
acetate in water.
5
Oobleck! Liquid or Solid?
• Overview:
Placed one cup of cornstarch into a
bowl. Then added a half cup of water
very slowly until the cornstarch/water
mixture was thick and gooey.
• Question:
What is Oobleck? Is it a solid or liquid?
6
Oobleck! Liquid or Solid?
•
Explanation:
A) The truth is that an Oobleck is a nonNewtonian fluid, neither solid nor liquid.
When a force (such as squeezing,
stirring, slapping) is applied to a nonNewtonian fluid, the fluid behaves like
a solid. Once the force returns to
normal, the molecules loosen and the
mixture is once again slimy.
B) As a result, non-Newtonian fluids act
like liquids when the molecules are
relaxed and act like solids when force
is applied.
7
The Candle, the Beaker
and the Water?
• Overview:
Filled a container with water about ¼”
deep. Lit a candle and set it on the
middle of the plate. Without letting the
beaker touch the candle, cover the
candle without the upside down beaker.
• Question:
Why does the water rise when the
beaker is upside down and the candle
burns out?
8
The Candle, the Beaker
and the Water?
• Explanation:
A) As the candle uses the limited
oxygen under the beaker, it creates
a low pressure relative to outside of
the beaker.
B) The higher air pressure outside the
beaker forces the water in the plate
to move up into the glass to make
the the pressure inside and outside
of the beaker same.
9
®
Mentos :
Diet Coke and
Coke Volcano?
• Overview:
Place one or several Mentos® candy
in a 2-Liter Diet Coke bottle. Step
back and watch for eruption like that
of a volcano.
• Question:
Why does putting a solid cause such
reaction to occur to a liquid?
10
®
Mentos :
Diet Coke and
Coke Volcano?
• Explanation:
A) The numerous small pores on the
candy's surface speed up the
release of carbon dioxide gas (the
bubbles and fizz) from the soda,
resulting in the release of excess
foam.
B) The surface of the candy is also
rough therefore causing that initial
“explosion” like a volcano.
11
®
Mentos :
Diet Coke and
Coke Volcano?
• Main Mentos contributors to the
reaction: gum arabic and gelatin
• Main Diet Coke contributors to the
reaction: caffeine, apsartame,
potassium benzoate
• Rough surface of Mentos provides
growth sites for the carbon dioxide
dissolved in Diet Coke
12